Gray vat dye and process of making same.



.disulfid or a sodium sulfid solution.

JULIUS IIOFFMANN, OF BASEL, SWITZERLAND,

ASSIGNOR TO SOCIETY OF CHEMICAL INDUSTRY IN BASLE, OF BASEL, SWITZERLAND.

GRAY VAT DYE AND PROCESS OF MAKING SAME.

Specification of Letters Patent.

Patented. March 23, 1909.

Application filed July 14, 1908. Serial No. 443,434.

T 0 all whom it may concern;

Be it known that I, JULIUS I'loiuuiimu, doctor of philosophy and chemist, a citizen of the Swiss Republic, and resident of Basel, Switzerland, have invented a new and useful Gray V at Dycstufi and a Processof Making Same, of which the following is a full, clear, and exact specification.

I have found that by heating an arylainido derivative of -fZ-methylanthraquinone with sulfur to a high temperature new sulfurized dyestuffs are produced, which dye unmordanted cotton in an alkaline hydrosulfite vat, gray tints fast to washing. The manufacture of these new vat-dyes illustrated by the following examples: Example I: 25 parts of phcnylamido-2- methylanthraquinone are heate with 75 parts ofsulf'ur to 28()29U C. for 34 hours. The cooled mass is finely owdered and the excess of'sulfur is extracte from it by carbon The dyestuff thus obtained is a black powder which dissolves in concentrated sulfuric acid to a greenish black solution and in fuming sulfuric acid containing 24 per cent. SO to .a blackish olive solution. With alkaline re ducing agents it yields a brown vat from which cotton is dyed brownish gray tints fast to washing and light.

Example IIHLO parts of diphenyl or diparatolyl dianiido -2- methylanthra uinone are heated with 60-70 parts of su fur for about 3 hours at 280-290 C. The cooled mass is finely powdered and the mass of sulfur is extracted from it by carbon disulfid, the remaining dycstuff constituting a black owder. It dissolves in concentrated suluric acid to a blackish olive colored solution and in fuming sulfuric acid containing 24 per cent. of SO to a bluish blacksolution. With soda lye and hydrosulfite it'vields a brown vatfrom which cotton is dyed beautiful gray tints.

If in the foregoing examples the )ecificd arylamido derivatives of Z-methylantlu'aquinone be replaced by another arylamido derivative of 2--methylanthraq uinone, as for instance orthotolylamido-2 methylanthraquinone, paratolylamido 2 methylanthraquinone, alphanaphthylani.ido-Z-methylanthraquinone, 'betanaplithylai'nido 2 methylanthraquinone, monophenyl-I: 4 diamido 2- niethylanthraquinone etc., dyestuffs of similar ropertics are obtained.

I hat I claim-is:

l. The described process for the manufacture of gray vat-dyestuffs, which consists in heating an arylamido derivative of Z-methylanthraquinone with sulfur to a high temper ature.

2. As new articles of manufacture, the vat-dyestuffs, obtainable by heating an arylamido derivative of 2-methylanthraquinone with sulfur to a high temperature, constitut ing, in dry state, black owders, soluble in concentrated sulfuric acid with a greenishblack to blackish olive coloration, soluble in fuming sulfuric acid of 24 per cent. SO with a blackish olive to bluish black color. insoli ble in the usual organic solvents and yield' 1g with alkaline reducing agents brown vats dyeinq cotton gray shades.

In witness whereof I have hereunto signed myiliaine this first day of July 1908, in the presence of two subscribing witnesses.

JULIUb HOFFMANN.

Witnesses I ERNST WAGNER, AMAND RITTER. 

